Dust seal for an industrial mixer



Jan. 20, 1959 P. s; HETEJI 2,869,900

DUST SEAL FOR AN INDUSTRIAL MIXER Filed Sept. 16, 1957 PAL) L S. H ETEJI E MLM'JZA.

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nnsr SEAL son AN INDUSTRIAL MIXER Paul S. Hetejl, North Plainfieitl, N. 1., assignor to Worthington Corporation, Harrison, N. J., a corporation of Delaware Application September 16, 1957, Serial No. 683,992

1 Claim. (Cl. 285-9) This invention relates to an improved seal between a rotating mixing drum and a stationary discharge housing unit of an industrial mixer, and particularly to a seal which maintains its eficiency despite irregular axial and radial movements of the rotating mixing drum. 7

During operation of the rotating mixing drum there is a continual shifting of the batch material being mixed therein, and this results often in end float and out-of-round run out of the mixing drum. Accordingly, the seal between this unit and the stationary discharge housing unit, as well as allowing for relative rotation of the units, must also allow for limited irregular axial and radial movements of the rotating mixing drum in order to etfectively prevent dust contamination of the plant atmosphere.

It is therefore an object of the present invention to provide an improved seal which will meet these operational requirements. I

More specifically, it is an object of the present invention to provide a seal between the rotating and stationary units or an industrial mixer in which sealing efficiency is maintained despite limited irregular movements of the rotating mixing drum.

To accomplish this, in the seal of the present invention, a circular rotary seal in continuous sealing engagement about the periphery of the housing unit opening is connected to a freely flexing portion of a flexible element mounted in the mixing drum opening. Thus, when there are irregular movements of the mixing drum during its operation, these movements are taken up by flexuring of the flexible element and therefore do not adversely atfect the efliciency of the rotary seal.

The invention will be better understood when considered in connection with the accompanying specification and drawings forming a part thereof, in which:

Figure l is a vertical view along the longitudinal axis of an industrial mixer.

Figure 2 is an enlarged cross-sectional view of the circled portion of Figure 1 showing in detail the seal of the present invention connected between the discharge housing unit and the mixing drum.

In Figure 1, the stationary discharge housing unit and the rotatable mixing drum are generally designated 1 and 2 respectively.

While not shown, it will be understood that the mixing drum 2 is adapted to be rotated by suitable connection to motor driven rollers or the like. Accordingly, any batch material such as dry plastic powders, salts or the like, delivered into the drum are mixed by the agitating action of the blades 3 suitably mounted about the interior of the mixing drum 2.

In accordance with usual industrial mixer operation, there is an initial mixing period when the transfer chute 4 connected to pivotal arms 5 is in its position to the left within the stationary discharge housing unit 1. At this time, the door 6 rotatably mounted on the arm 7 connected to the upper portion of the transfer chute 4 is in its closed position about the discharge end opening of the 2,869,900 Patented Jan. 2o, 1959 However, in the subsequent operation of the industrial.

mixer, the chute 4 is swung to the right into the position shown in phantom perspective, the lifting blades 9 deliver batch material into the chute 4 for transfer into the stationary discharge housing unit 1, and it is then necessary to have a suitable seal, such as that generally designated 10 in Figure l, in order to prevent dust from contaminating the plant atmosphere.

To better understand the details of construction of the seal 10, attention is directed to the enlarged view thereof shown in Figure 2. The various elements comprising this seal are essentially circular in shape when viewed in the direction of the arrow A. Thus, a mounting element 11 having a central opening 12 therein, is connected by circumferentially spaced bolt means 13 about the periphery of the end opening 8 of the mixing drum 2, and the chute 4 when in the position transfering the batch material, extends through the end opening 14 of the housing unit 1 and through the said mounting element central opening 12. The other elements of the seal 10 are then connected between the housing unit 1 and mixing drum 2 encircling the transfer chute 4 to form a sealed passageway for the batch material being transfered.

These other elements of the seal 10 consist in part of a flat flexible element 15 and a spacer ring 16, each of which is connected by the bolt means 17 to the side of the mounting element 11 facing the housing unit 1. More specifically, the flexible element 15, which may consist of neoprene with a two-ply Duck center, is connected about the periphery of its central opening 18 to the mounting element 11, with the spacer ring 16 interposed between it and the mounting element 11. Thus, the outer portion of the flexible element 15 is spaced the distance B from the mountinge'lement 11 and to this extent is not restricted from flexing by the mounting element 11.

Connected about this outer portion of the flexible element 15 by the bolt means 19 is a circular rotary seal 20 consisting of a pair of sealing rings 21 held in spaced relationship by the spacing rings 22. Sealingly engaged between these sealing rings 21 is an inturned circumferential flange 23 formed on one end of cylindrical element 24 which at the other end has an outturned circumferential flange 25 through which it is mounted by the bolt means 26 about the periphery of the stationary discharge housing unit opening 14.

Thus, in the seal 10 as herein described, during rotation of the mixing drum 2 relative to the stationary housing unit 1, the circular rotary seal 2 maintains continuous sealing engagement with the inturned flange 23 to prevent the escape of dust from the batch material being transfered by the chute 4. Further, this sealing engagement of the rotary seal 26 with the inturned flange 23 is not adversely aflected by any irregular axial or radial movements of the rotating mixing drum 2 resulting from the shifting of the batch material therein since these movements are taken up by appropriate flexuring of the flexible element 15 on which the circular rotary seal 29 is mounted.

It will be understood that a seal according to the present invention is not to be limited solely to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention as defined by the claim.

What is claimed is:

A seal between a rotatable mixing drum having a dis charge opening in one end and a non-rotatable housing unit having an opening therein to receive materials discharging from said rotatable drum, a mounting element having an opening therein connected about the periphery of the drum. discharge opening, a spacer ring connected 3 about the periphery of the mounting element opening on the side thereof nearest the housing unit, a flat flexible element having an opening therein connected about the periphery of itssaid opening to'thespacer ring so that its outer portion being spaced from the mounting element is free to flex, a hollow cylindrical-element connected at one end about the periphery of the housing unit opening and extending laterally inthe direction of the flexible element,

inturned circumferential flange formed in the extending end of saidcylindrical element in proximate spaced relationship to the outer portion of the flexible element, and'circular sealing means connected to said flexible element to sealingly engage said inturned circumferential flange, said circular sealing means comprising apeir of sealing rings connected to opposite sides of a spacer ring and adapted to sealingly engage the intnrned circumferential flange therebetween, whereby during rotation of. the mixing drum a seal is maintained while the flexible element permits limited irregular axial and radial movements in the mixing drum.

Rockburg Mar. 6, 19-51 Yantes et al. Aug. 7, 1951 

